(a) Technical Field
The present invention relates to a fuel efficiency measuring system for a fuel cell vehicle. More particularly, it relates to an improved fuel efficiency measuring system for a fuel cell vehicle which simplifies both various valves and hydrogen lines within the system and modulizes its individual elements.
(b) Background Art
A fuel cell is an electricity generation system that does not convert chemical energy of fuel into heat by combustion, but rather electrochemically converts the chemical energy directly into electrical energy in a fuel cell stack. The fuel cell can be applied to the electric power supply of small-sized electrical and electronic devices, for example portable devices, as well as industrial and household appliances and vehicles. The fuel cell stack is mounted to a fuel cell vehicle to produce electricity through an electrochemical reaction in which hydrogen and oxygen in the air are used as fuels. During the electrochemical reaction hydrogen is supplied from a hydrogen tank in a fuel supply system and oxygen in air is supplied from an air blower in an air supply system.
Those skilled in the art would realize that it is impossible to evaluate the efficiency of a hydrogen fuel cell vehicle in which a fuel cell stack is mounted using previous fuel consumption measuring methods which have been applied to general internal combustion engines, because typically these method measure the amount of carbons contained in exhaust. Since carbons are not present in the hydrogen fuel cell process, a new fuel efficiency measuring method is required which can be applied to hydrogen fuel cell vehicles.
Considering the deficiency in the market, the applicant filed a patent application, Korean Patent No. 10-0831567 and U.S. Patent Application Publication No. 2009/0030625, entitled “Fuel Efficiency Measurement System and Method for Fuel Cell Vehicle” filed May 29, 2008 and is hereby incorporated by reference. This previously filed application relates to a system and a method for accurately measuring the fuel efficiency of a fuel cell vehicle that uses hydrogen as a fuel. However, this fuel efficiency measuring system and method suffers from a number of disadvantages.
One noted disadvantage is that the previous system is that it is made up of many parts. For example, FIG. 2 is a diagrammatic view illustrating a conventional fuel efficiency measuring system for a fuel cell battery as described above. As can be seen from the figure, the previously designed fuel efficiency measuring method includes a hydrogen tank 1 is configured to supply hydrogen to the fuel cell stack, an electronic scale that is configured to measure the weight of the hydrogen tank (1), a plurality of valves (V4, V5, V6, and V7) installed in hydrogen supply lines that are connect the hydrogen tank 1 and to the vehicle and are located between the hydrogen tank 1 and the vehicle. Additionally, a break-away coupler is coupled to a fuel efficiency measuring unit to the vehicle and is configured to prevent leakage of hydrogen when the vehicle is deviated. Purge hydrogen tank 2 is configured to remove residual air in the lines before a test of the system may be conducted. More specifically, valves V1, V2, and V3 are configured to control the direction of hydrogen discharged from the purge hydrogen tank (2), and a line gauge (G1) is configured to measure the pressure of the hydrogen on a downstream side of a regulator or more specifically a high pressure regulator (HPR1). Additionally, a 3-way valve (V8) is configured to redirect the supply direction of hydrogen between a vehicle side hydrogen tank 3 and a fuel efficiency measuring hydrogen tank 1. As can be seen from FIG. 2, the previous system is made up of numerous parts thereby making the assembly complex. Accordingly, the assembling processes may be difficult and time consuming. Thus, it is difficult to manufacture the system and considerably expensive.
Additionally when a coupler or more specifically a quick coupler C1 is connected to a hydrogen tank to allow an electronic scale to accurately measure the weight of the hydrogen tank is separated, a residual hydrogen pressure of about 350 bars exists between the outlet end of the hydrogen tank and the quick coupler. Thus, it is difficult to separate the quick coupler from the system when needed.